PCI/ACPI: Decode _OSC bitmasks symbolically

This updates _OSC-related messages to be more human-readable.  We now always
show the features we declare support for (this was previously invisible) as
well as the features we are granted control of.

Typical changes:

  -acpi PNP0A08:00: Requesting ACPI _OSC control (0x1d)
  -acpi PNP0A08:00: ACPI _OSC control (0x1d) granted
  +acpi PNP0A08:00: _OSC: OS supports [ExtendedConfig ASPM ClockPM Segments MSI]
  +acpi PNP0A08:00: _OSC: OS now controls [PCIeHotplug PME AER PCIeCapability]

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 67 insertions, 17 deletions

diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index 65aefcf78552..924ad92852c1 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -127,6 +127,55 @@ static acpi_status try_get_root_bridge_busnr(acpi_handle handle,
         return AE_OK;
 }
 
+struct pci_osc_bit_struct {
+        u32 bit;
+        char *desc;
+};
+
+static struct pci_osc_bit_struct pci_osc_support_bit[] = {
+        { OSC_PCI_EXT_CONFIG_SUPPORT, "ExtendedConfig" },
+        { OSC_PCI_ASPM_SUPPORT, "ASPM" },
+        { OSC_PCI_CLOCK_PM_SUPPORT, "ClockPM" },
+        { OSC_PCI_SEGMENT_GROUPS_SUPPORT, "Segments" },
+        { OSC_PCI_MSI_SUPPORT, "MSI" },
+};
+
+static struct pci_osc_bit_struct pci_osc_control_bit[] = {
+        { OSC_PCI_EXPRESS_NATIVE_HP_CONTROL, "PCIeHotplug" },
+        { OSC_PCI_SHPC_NATIVE_HP_CONTROL, "SHPCHotplug" },
+        { OSC_PCI_EXPRESS_PME_CONTROL, "PME" },
+        { OSC_PCI_EXPRESS_AER_CONTROL, "AER" },
+        { OSC_PCI_EXPRESS_CAPABILITY_CONTROL, "PCIeCapability" },
+};
+
+static void decode_osc_bits(struct acpi_pci_root *root, char *msg, u32 word,
+                            struct pci_osc_bit_struct *table, int size)
+{
+        char buf[80];
+        int i, len = 0;
+        struct pci_osc_bit_struct *entry;
+
+        buf[0] = '\0';
+        for (i = 0, entry = table; i < size; i++, entry++)
+                if (word & entry->bit)
+                        len += snprintf(buf + len, sizeof(buf) - len, "%s%s",
+                                        len ? " " : "", entry->desc);
+
+        dev_info(&root->device->dev, "_OSC: %s [%s]\n", msg, buf);
+}
+
+static void decode_osc_support(struct acpi_pci_root *root, char *msg, u32 word)
+{
+        decode_osc_bits(root, msg, word, pci_osc_support_bit,
+                        ARRAY_SIZE(pci_osc_support_bit));
+}
+
+static void decode_osc_control(struct acpi_pci_root *root, char *msg, u32 word)
+{
+        decode_osc_bits(root, msg, word, pci_osc_control_bit,
+                        ARRAY_SIZE(pci_osc_control_bit));
+}
+
 static u8 pci_osc_uuid_str[] = "33DB4D5B-1FF7-401C-9657-7441C03DD766";
 
 static acpi_status acpi_pci_run_osc(acpi_handle handle,
@@ -340,10 +389,14 @@ acpi_status acpi_pci_osc_control_set(acpi_handle handle, u32 *mask, u32 req)
                         goto out;
                 if (ctrl == *mask)
                         break;
+                decode_osc_control(root, "platform does not support",
+                                   ctrl & ~(*mask));
                 ctrl = *mask;
         }
 
         if ((ctrl & req) != req) {
+                decode_osc_control(root, "not requesting control; platform does not support",
+                                   req & ~(ctrl));
                 status = AE_SUPPORT;
                 goto out;
         }
@@ -363,7 +416,7 @@ EXPORT_SYMBOL(acpi_pci_osc_control_set);
 static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm,
                                  int *clear_aspm)
 {
-        u32 support, control;
+        u32 support, control, requested;
         acpi_status status;
         struct acpi_device *device = root->device;
         acpi_handle handle = device->handle;
@@ -379,6 +432,8 @@ static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm,
                 support |= OSC_PCI_ASPM_SUPPORT | OSC_PCI_CLOCK_PM_SUPPORT;
         if (pci_msi_enabled())
                 support |= OSC_PCI_MSI_SUPPORT;
+
+        decode_osc_support(root, "OS supports", support);
         status = acpi_pci_osc_support(root, support);
         if (ACPI_FAILURE(status)) {
                 dev_info(&device->dev, "_OSC failed (%s); disabling ASPM\n",
@@ -393,8 +448,8 @@ static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm,
         }
 
         if ((support & ACPI_PCIE_REQ_SUPPORT) != ACPI_PCIE_REQ_SUPPORT) {
-                dev_info(&device->dev, "Not requesting _OSC control (we support %#02x but %#02x are required)\n",
-                         support, ACPI_PCIE_REQ_SUPPORT);
+                decode_osc_support(root, "not requesting OS control; OS requires",
+                                   ACPI_PCIE_REQ_SUPPORT);
                 return;
         }
 
@@ -404,21 +459,17 @@ static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm,
 
         if (pci_aer_available()) {
                 if (aer_acpi_firmware_first())
-                        dev_dbg(&device->dev,
-                                "PCIe errors handled by BIOS.\n");
+                        dev_info(&device->dev,
+                                 "PCIe AER handled by firmware\n");
                 else
                         control |= OSC_PCI_EXPRESS_AER_CONTROL;
         }
 
-        dev_info(&device->dev,
-                 "Requesting ACPI _OSC control (0x%02x)\n", control);
-
+        requested = control;
         status = acpi_pci_osc_control_set(handle, &control,
                                           OSC_PCI_EXPRESS_CAPABILITY_CONTROL);
         if (ACPI_SUCCESS(status)) {
-                dev_info(&device->dev,
-                         "ACPI _OSC control (0x%02x) granted\n",
-                         control);
+                decode_osc_control(root, "OS now controls", control);
                 if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_ASPM) {
                         /*
                          * We have ASPM control, but the FADT indicates
@@ -427,12 +478,11 @@ static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm,
                         *clear_aspm = 1;
                 }
         } else {
-                dev_info(&device->dev,
-                        "ACPI _OSC request failed (%s), "
-                        "returned control mask: 0x%02x\n",
-                        acpi_format_exception(status), control);
-                dev_info(&device->dev,
-                         "ACPI _OSC control for PCIe not granted, disabling ASPM\n");
+                decode_osc_control(root, "OS requested", requested);
+                decode_osc_control(root, "platform willing to grant", control);
+                dev_info(&device->dev, "_OSC failed (%s); disabling ASPM\n",
+                        acpi_format_exception(status));
+
                 /*
                  * We want to disable ASPM here, but aspm_disabled
                  * needs to remain in its state from boot so that we